docs: def _emiss_ee(self, Eph):
          """
          Electron-electron bremsstrahlung emissivity per unit photon energy
          """
          if self.weight_ee == 0.0:
              return np.zeros_like(Eph)
  
          gam = np.vstack(self._gam)
          # compute integral with electron distribution
          emiss = c.cgs * trapz_loglog(
              np.vstack(self._nelec) * self._sigma_ee(gam, Eph),
              self._gam,
              axis=0,
          )
          return emiss